Most of us probably remember playing hide-and-seek as a kid. There seemed to be so many places where we could seek cover and never be found. Today, finding a place where you can't be seen is becoming increasingly difficult. Surveillance cameras seem to watch our every move. They're in stores, our offices, over our roads, even in our homes. Soon, cameras will be augmented by new tracking technologies that will detect our wireless devices, too.


Photo courtesy Digital Angel Corporation
By the end of 2001, location-tracking technologies will be able to locate people nearly anywhere.

By using global positioning system (GPS) satellites and local, land-based networks, these new systems will use wireless radio signals to find you wherever you are. If your cell phone is equipped with a GPS receiver, as will be required by the U.S. Federal Communications Commission (FCC) beginning in October 2001, it will be nearly impossible to conceal your location. (Developers have assured consumers that they will be able to opt out of these networks and remain anonymous if they so choose.)

The use of location-tracking technologies means that people will be easier to find during emergencies. But it also means that marketers will be able to send us unsolicited advertising on our cell phones as we pass by or through retail stores. In this edition of How Stuff WILL Work, we will look at three types of location-tracking technology and see how they will be able to seek you out no matter where you're hiding.

Watching Over You
By November 2001, Digital Angel will allow you to not only locate someone, but also check on that person's health. Such a system will especially assist those trying keeping track of patients or elderly parents. Digital Angel combines wireless radio signals, GPS satellites and a ground-based data center to continuously track someone's location. Subscribers to the service will be able to log on from any Internet-connected device to check on a loved one.


Digital Angel uses GPS satellites and an AT&T wireless network to track people wearing a BioSensor watch and GPS-equipped pager device.

Here are the various components that make up the Digital Angel system:

  • Biosensor - Embedded in a wristwatch, this biosensor touches the skin and reads a person's vital signs, including temperature and pulse. A special algorithm allows the system to determine if the person has suddenly fallen down, a feature useful for some at-risk patients.


Photo courtesy Digital Angel
A person would have to wear this special watch and pager in order to be tracked by the Digital Angel network.

  • Pager device - Data from the biosensor is sent wirelessly to a pager device that has a GPS receiver and a cellular packet module or transceiver, which enables it to upload this information to a satellite. A microprocessor in the pager organizes the data flow from the GPS receiver and transceiver. Both the biosensor watch and the pager device will come with a rechargeable battery.
  • GPS satellites - Digital Angel uses these satellites and a remote monitoring station to continually ping (bounce radio signals to) the person's pager device. Radio signals from the satellite get a fix on a position, and the satellite then transmits a longitude and latitude to a GPS receiver.
  • AT&T wireless network - Once a person has been located, their information can be sent through cellular data packets to a wireless network. The data is sent over a frequency range of 800 to 900 MHz.
  • Delivery system - While AT&T provides the transmission of signals, Digital Angel provides the hosted data center. There are two of these centers in the United States, one in New York and one in Maryland. Proprietary software allows subscriber devices to interface with the data center. Users can log on and get information, along with a map of a person's location.

Digital Angel relies directly on satellite transmission -- it doesn't use cell towers. The company is working on integrating relay devices into aircraft and ships. This would make transmissions easier and more reliable.

As of May 2001, consumers can view and pre-order the biosensor watch and pager device. There are two watches, one for kids and one for adults. The components will be available in October 2001 for $299, and service will cost between $19.95 and $49.95 per month depending on the service plan you choose.

A New 911
In America, we learn from an early age to call 911 when there's an emergency. When we dial 9-1-1, the call is automatically forwarded to a public-safety answering point (PSAP), also called a 911 call center. Typically, the caller will tell the 911 operator about the emergency and his or her location. In 2001, most areas are also serviced by Enhanced 911 (E-911), which allows the operator to trace the phone call and access the address that the call is coming from.

Why 911?
Have you ever wondered why 911 was chosen as the universal emergency code in the United States? Prior to the 1960s, there was no universal number to call for emergency help. In 1967, the Federal Communications Commission met with AT&T to establish such a number, according to the National Emergency Number Association (NENA). But why did they choose 911? Why not 422 or 111?

There are several reasons why 911 was chosen. It's a short, easy to remember number, but more importantly, 911 was a unique number -- it had never been designated for an office code, area code or service code.

On February 16, 1968, Alabama Senator Rankin Fite made the first 911 call in the United States in Haleyville, Alabama. The Alabama Telephone Company carried the call. A week later, Nome, Alaska, implemented a 911 system. In 1973, the White House's Office of Telecommunication issued a national statement supporting the use of 911 and pushed for the establishment of a Federal Information Center to assist government agencies in implementing the system.

The problem with the 911 system is that it has been slow to recognize the growing number of phone calls coming from cell phones. There are more than 115-million wireless subscribers in the United States, according to the Cellular Telephone Industry Association (CTIA), with an additional 46,000 Americans subscribing to wireless service every day.

So how does this affect 911 calls? The National Emergency Number Association (NENA) estimates that 150-million calls were made to 911 in 2000, and 45-million of those calls were made on cell phones. That's up from the 4.3-million wireless phone calls made to 911 in 1990, and NENA believes the number will increase to 100-million by 2005.

The FCC has ruled that cell-phone providers must equip their phones with GPS receivers by October 2001. This will give authorities the ability to locate a cell-phone user who has called the 911 service. Enhanced wireless 911 is being implemented in three stages:

  • Phase 0 - This is the basic 911 process. Wireless calls are sent to a PSAP. Service providers must direct a call to PSAP even if the caller is not a subscriber to their service.
  • Phase I - The FCC's rule requires that a phone number display with each 911 call, allowing the PSAP operator to call back if there is a disconnection. The FCC deadline for Phase I was April 2000.
  • Phase II - The final phase requires carriers to place GPS receivers in phones in order to deliver more specific latitude and longitude location information, called Automatic Location Identification (ALI). Phase II is designed to bring wireless calls up to the level of E-911 calls, which means the caller's phone number and location is identified. Carriers must begin selling and activating ALI-capable phones by October 1, 2001. The remaining obstacle is the upgrading of PSAP equipment to handle this new tracking technology. When the upgrade is complete, cell-phone callers will be pinpointed to within 300 feet (91 m) of their location.

Without Phase II, a caller's location can only be narrowed down to the cell from which the call originated. When Phase II is implemented, a cell-phone user's phone number, or Automatic Number Identification (ANI), and the address and location of the receiving-antenna site will be sent to the E911 Tandem, the switch that routes 911 calls to the appropriate PSAP based on the ANI-defined geographic location. Once the caller's voice and ANI are transferred to PSAP, the PSAP operator will be able to view a graphic display that shows the longitude and latitude of the person as accessed through GPS satellites. The operator's computer will link to the ALI database, which stores address data and other information.

Attention Shoppers
In the previous two sections, we discussed networks that will cover very wide areas. But there are also some tracking systems in development that will be used on a much smaller scale. For example, a shopping mall might want to have a local network that tracks shoppers, but it doesn't need a system that covers an entire city. To fill this niche, PanGo Networks is developing what it calls a Proximity Platform.


PanGo's Proximity Platform sets up zones of radio signals that send coupons and other announcements to a consumer's wireless device.

The Proximity Platform basically sets up wireless zones within defined areas. These zones are called hot spots. When a wireless user enters a hot spot, his or her device is detected. Content such as advertisements and coupons is generated and displayed on the device. Imagine that the entire mall is a computer screen with clickable buttons. As such, the wireless-device user would be the mouse, and the hot zones would be the buttons. When you enter a hot zone, you click on a button, which delivers content to your PDA or cell phone. Using the shopping mall as the example, let's look at the various components of the Proximity Platform:

  • Site Manager - The site manager is the heart of the system. This software will allow operators of short-range radio networks to set up zones in high-traffic areas to detect wireless devices.
  • Content Server - Within each store of the mall, there will be a local content server that is connected to the Proximity Platform network. These servers will have a range that is limited to targeted areas of each store.
  • Bluetooth or 802.11 - These short-range radio signals, which allow electronic devices to communicate with each other, will be used by the Proximity Platform to create the "hot spots."

The PanGo system is based on spaces. It will be able to track you as you walk through a mall and even detect how long you spend in certain spaces. These spaces are defined by the site manager and the content server. As a person with wireless device enters a space, the content server communicates with the site manager. The site manager then delivers content to the wireless device. PanGo spokesperson Charlie Day said that the system will give users the ability to opt out and remain anonymous.

Day said that the PanGo system will not be ready for at least another year, but you will see wireless 911 and Digital Angel implemented at the end of 2001. In coming years, there are sure to be more location-tracking systems developed. Imagine a world in which anyone can log into a system to find out exactly where you are at any given moment. Developers admit that privacy issues will be an obstacle to widespread acceptance of their services.

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